Manufacture of wax acids



Patented May 31, 1938 Richard James Butz and Robert Charles vCantelo, Whiting, Ind., assignors to Sinclair Refining Company, New York, N. Y., a corporation of Maine No Drawing. Application September so. 1936,

Serial No. 103,367

3 Claims. I, (Cl. 260116) This invention relates to improvements in the manufacture of so-called wax acids, the organic acids produced by oxidation of paraffin wax hav-- ing acid numbers approximating 120 or higher,

higher and molecular weights in the. general neighborhood of 400. The invention is of special value in the manufacture of wax acids for compounding, as aluminum salts of the wax acids,

with petroleum lubricatingolls to lower the pour point of such oils as described in an application filed June 11, 1935, Serial Number 26,038 by Edwin J. Barth and Ralph P. Corlew.

According to this invention, such wax acids are prepared by blowing air through parailln wax of melting point approximating 130-132 F. at a rate ranging from 0.5 to 10.0 cubic feet per hour per pound of wax mixture while maintain. ing a temperature of 220-250 F., stopping the oxidation before the acid number and saponiflcation number of the wax mixture exceeds 70 and 125, respectively, and separating the wax acids from the wax mixture. Separation of the wax acids from the wax mixture can be effected in any convenient manner, by saponiflcation and separation of the resulting soap or byextraction with an appropriate solvent such as isopropyl alcohol for example. A blowing rate approximating 2 cubic feet per hour per pound of wax mixture is particularly advantageous. The yield of wax acids is improved by blowing the wax while maintaining a temperature approximating 250 F. until the saponification number of the wax mix ture approximates 40-50 and then reducing the temperature to about 230 F. and continuing the blowing at this lower temperature, the temperature being reduced either in a single step or in several steps. 4

The following examples. will illustrate the practice of the invention:

Example I 2% kilograms of paraflin wax having a nielting point of 130 132 F. and 37.5 grams of stearic 4 acid are charged into a steam jacketed steel pot equipped with a paddle type stirrer. Air is blown through the charge in the pot at a rate of about llcublc feet per hour while maintaining a temperature of 250 F., the mixture in the pot being vigorously agitated throughout the blowing, care being taken to limit the agitation to a degree avoiding the formation of an air emulsion with the wax mixture. The blowing is continued until the acid number and saponiilcation number of the mixture reaches 3'! and 19.3, respectively.

saponification numbers approximating or" The wax acids are then saponified by heating for 1 hour at 172 F. with a 20 Baum aqueous solution of sodium hydroxide in proportion containing about thatamount of sodium hydroxide theoretically required to react with the wax acids 5 and the temperature of the mixture is then raised to F. and maintained at 190 F. for 30 minutes. The resulting mixture including the sodium. salts of the wax acids is diluted with five times its 'volume of water, suiiicient acetone or other suit- 10 able organic solvent is added to resolve the resulting emulsion, and the aqueous soap solution. is separated by decantation from the supernatant layer of unsaponifiable matter.

Example II The operation is the same as that described in Example I, except that the blowing is continued until the acid number and saponification number of the wax mixture reach 45.5 and 92, respective- 2.0 1y. A somewhat higher yield of wax acids somewhat more effective in the form of aluminum salts as pour depressors is obtained.

Example III 2 25 2 kilograms of parafiin wax having a melting point of l30-132 F. and 37.5 grams of stearic acid are charged into a steam jacketed steel pot equipped with a paddle type stirrer. Air is blown through the charge in the pot while maintain- 30 ing a temperature of 250 F. until the saponiflca tion number of the wax mixture reaches 43.5, the temperature is then reduced toabout 230 F. and the blowing is continued at this lower temperature until the acid number and saponiflcation 5 numberreach 54.4 and 103, respectively. The wax acids produced are separated by saponification with'sodium hydroxide as in the first example A yield of wax. acids somewhat higher than that obtained in the second example is ob- 40 tained, these wax acids being about'as efiective, in the formpf aluminum salts, as pour depressors benzol as described in that prior application. The

tially higher than those specified, tend to produce 66 salts of the wax acids prepared as described in the foregoing examples were effective, severally, to reduce the pour test of a Pennsylvania lubricating oil originally having a pour test of 25 F. p

to -10 F. or lower added in amounts of 0.5% (by weight) on the oil. A

The addition of stearic' acid to the charge of paramn wax subjected to oxidation as in the foregoing examples is not essential but does facilitate the progress of the oxidation.

We claim:

1. In the manufacture of wax acids, the improvement which comprises blowing air through paraflin wax of melting point approximating 130-132 F. at a rate of 0.5-10 cubic feet per hour per pound of wax mixture while maintaining a temperature of 220-250 F., stopping the oxidation before the acid number and saponification number of the wax mixture exceed 70 and 125, respectively, and separating the wax acids 'from the wax mixture.

2,118,915 wax acids which in the form of aluminum salts 2. In the manufacture of wax acids, the improvement which comprises blowing air through param'n wax of melting point approximating 130-132 F. at a rate approximating 2 cubic feet per hour per pound of wax mixture while maintaining a temperature of 220-250 F., stopping the oxidation. before the acid number and saponification number of the wax mixture exceed 70 and 125, respectively, and separating the wax stopping the oxidation before the acid number and saponiflcation number of the wax mixture exceed '70 and 125, respectively, and separating the wax acids from the wax mixture.

ROBERT CHARLES CANTEIlO. RICHARD JAIWES BUTZ. 

